Running head: ORAL CONTRACEPTIVE AND OVARIAN CANCER 1 Week 4 Case Study Question 1: Which investigations need to be reviewed by an institutional review board? Does this investigation need to be reviewed? All human subject research must be reviewed by an IRB before the research can begin ( , 2016). This investigation is a case-control study and does involve human subjects, so it does need IRB approval before initiation. Question 2: What types of bias are of particular concern in this case-control study? What steps might you take to minimize these potential biases? In our epidemiology CLP session, we discussed recall bias, which is the human being’s ability to recall information. In a case-control study, it is a retrospective study, so the disease has already been present. Recalling past exposure can be an issue with this type of study. Another type of bias that can be prone to a case-control study is selection bias. This occurs when a case or control is either selected or excluded from a study because of certain characteristics they have which resemble the exposure ( , 2016). In order to minimize selection bias in this type of study, choosing the controls from more than one setting is a preferable choice. Choosing the cases from a hospital setting and choosing the controls from a population or neighborhood setting may be a better representation of the population of those who produced the cases ( , 2016). Question 3: List, in logical sequential order, the table shells you might use to analyze or present the CASH study data. Table shells are frequency distributions or 2x2 tables that contain appropriate titles and labels, but do not contain data. I would use the following information to construct my table shell. 1. Age 2. Geographic location 3. Ever use Contraceptive 4. Never Use Contraceptive 5. Have cancer 6. Do not have cancer Question 4: From these data, can you calculate the risk of ovarian cancer among oral contraceptive users? Why or why not? Relative risk cannot be calculated in case control studies. The odds ratio is what a case-control study would use to calculate cumulative incidence. Odds ratio is an estimate of relative risk of a disease attributable to exposure if the incidence of the disease is low (Hogue et al., 1983). Question 5: Describe the rationale behind using the odds ratio as an estimate of the risk ratio. When is the odds ratio not an appropriate estimate of the risk ratio? The odds ratio is the association of exposure and disease in a case control study (Bonita et al., 2006). The odds ratio is determined by the odds of exposure from the diseased and the odds of exposure from the non-diseased. The relative risk is the ratio of risk of contracting the disease from
Running head: ORAL CONTRACEPTIVE AND OVARIAN CANCER 2 those who have been exposed and those who have not (Bonita et al., 2006). Since case-control studies are retrospective, meaning the cases either have the disease or are dead, it only makes sense to calculate the odds of contracting the disease by exposure and not the risk of it. In order for the odds
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- Winter '15
- Epidemiology, Case-control study, Study design